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1.
Wajdi Halabi Kris Steenhaut Marnix Goossens Thu-Huong Truong Ann Nowé 《Photonic Network Communications》2012,23(3):217-229
Routing, connection setup, and path computation are well-known problems in multi-domain networks, which have been largely
analyzed in pure IP (packet) networks. In circuit-switched optical multi-domain networks, there remain, however, a number
of routing and path computation challenges. Traffic grooming means combining a number of low-speed traffic streams so that
the high capacity of each lightpath may be used as efficiently as possible, as path computation implements the core of the
grooming function, it is obvious that solutions for the traffic grooming problem in optical multi-domain networks are still
not sufficiently investigated. In this study we propose a methodology to address the problems of routing, connection setup,
and traffic grooming in optical multi-domain networks, which adapts a two-level hierarchical routing scheme and full-mesh
topology abstraction algorithm to improve routing scalability and lower inter-domain blocking probabilities; additionally
our proposed methodology adapts a scheme for traffic grooming in DWDM multi-domain networks to improve the resources usage.
To test our proposed methodology we propose a detailed IP/MPLS-based ASON/GMPLS multi-domain multilayer test framework. 相似文献
2.
Routing for shared protection in multi-domain networks is more difficult than that in single-domain networks because of the scalability requirements. We propose a novel approach for shared protection routing in multi-domain networks where the key feature is a special Topology Aggregation. In this Topology Aggregation, only some potential intra-domain paths (intra-paths for short) are selected for carrying working and backup traffic between domain border nodes. The abstraction of each intra-path to a virtual edge makes the original multi-domain network to become an aggregated network. On the aggregated network, a single-domain routing algorithm for shared protection can be applied for obtaining the complete routing solutions. The experiments show that the proposed approach is scalable. Moreover it is close to the optimal solution in single-domain networks and outperforms the previously proposed scalable solutions in multi-domain networks. 相似文献
3.
Walter Colitti Kris Steenhaut Didier Colle Mario Pickavet Jan Lemeire Ann Nowé 《Photonic Network Communications》2011,21(3):238-252
The Internet traffic evolution has forced network operators to migrate toward an integrated infrastructure which brings the
IP and optical layers under a unified model. The integration between the two technologies has been facilitated by the development
of the Generalized Multi Protocol Label Switching. In the integrated scenario, Multilayer Traffic Engineering can be reinforced
with integrated routing techniques. Integrated IP/WDM routing facilitates the routing decision phase by allowing a node to
have a complete knowledge of the IP and WDM domains when accommodating traffic. This study focuses on integrated IP/WDM routing.
We analyze two basic policies widely discussed in literature: one policy prioritizes the traffic accommodation on the virtual
topology, while the other prioritizes the traffic accommodation on the physical topology. We show that both the mechanisms
do not lead to efficient resource utilization because they tend to congest one layer more than the other one. We propose an
adaptive heuristic which combines the advantages of both the policies. When accommodating traffic, the proposed approach selects
the appropriate layer depending on the resource utilization being experienced in the virtual and the physical topologies.
We demonstrate via simulations that the cross-layer resource optimization executed by the proposed scheme achieves significant
improvements in terms of blocking ratio. 相似文献
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Future transport networks will have to cope with the continuous growth of IP traffic. Furthermore, transport networks need to evolve so as to drastically reduce both deployment costs and operating expenses. A reasonable strategy to achieve this goal consists of simplifying the network architecture by reducing the number of layers. Assuming a peer model IP over optical network, we propose an integrated routing strategy that takes into account constraints and dynamic occupancy of both the IP and optical layers. The collaboration of both layers in the routing process leads to optimization of network performance. The main emphasis is on the implementation requirements of this grooming functionality using GMPLS-TE mechanisms. Simulation results show the benefits obtained by applying this strategy. 相似文献
6.
The demand assigned capacity management (DACM) problem in IP over optical (IPO) network aims at devising efficient bandwidth replenishment schedules from the optical domain conditioned upon traffic evolution processes in the IP domain. A replenishment schedule specifies the location, sizing, and sequencing of link capacity expansions to support the growth of Internet traffic demand in the IP network subject to economic considerations. A major distinction in the approach presented in this paper is the focus of attention on the economics of "excess bandwidth" in the IP domain, which can be viewed as an inventory system that is endowed with fixed and variable costs and depletes with increase in IP traffic demand requiring replenishment from the optical domain. We develop mathematical models to address the DACM problem in IPO networks based on a class of inventory management replenishment methods. We apply the technique to IPO networks that implement capacity adaptive routing in the IP domain and networks without capacity adaptive routing. We analyze the performance characteristics under both scenarios, in terms of minimizing cumulative replenishment cost over an interval of time. For the non-capacity adaptive routing scenario, we consider a shortest path approach in the IP domain, specifically OSPF. For the capacity adaptive scenario, we use an online constraint-based routing scheme. This study represents an application of integrated traffic engineering which concerns collaborative decision making targeted towards network performance improvement that takes into consideration traffic demands, control capabilities, and network assets at different levels in the network hierarchy. 相似文献
7.
Due to the explosive growth of data-related traffic driven by the Internet, network reliability becomes an important issue. We investigate various protection approaches to handle failures for dynamic traffic demands in IP/MPLS-over-WDM networks. An LSP can be protected at either the IP/MPLS layer or the optical layer. In IP/MPLS layer protection, an LSP is protected by providing a link-disjoint backup LSP between its end nodes. In optical layer protection, an LSP is protected by the backup lightpath of each lightpath traversed by the LSP. We present two integrated routing algorithms: hop-based integrated routing algorithm and bandwidth-based integrated routing algorithm (BIRA) to set up the restorable bandwidth-guaranteed paths efficiently. Then we present a multilayer protection scheme for multiclass traffic in such networks. This scheme takes into account the different QoS and recovery requirements of the traffic to provide protection capability either at the MPLS layer or at the optical layer in a cost-effective manner. We use the connection blocking probability and number of optical-electrical-optical conversions as performance metrics to compare various protection approaches. 相似文献
8.
《Optical Fiber Technology》2013,19(4):309-318
Overlay IP/MPLS over WDM network is a promising network architecture starting to gain wide deployments recently. A desirable feature of such a network is to achieve efficient routing with limited information exchanges between the IP/MPLS and the WDM layers. This paper studies dynamic label switched path (LSP) routing in the overlay IP/MPLS over WDM networks. To enhance network performance while maintaining its simplicity, we propose to learn from the historical data of lightpath setup costs maintained by the IP-layer integrated service provider (ISP) when making routing decisions. Using a novel historical data learning scheme for logical link cost estimation, we develop a new dynamic LSP routing method named Existing Link First (ELF) algorithm. Simulation results show that the proposed algorithm significantly outperforms the existing ones under different traffic loads, with either limited or unlimited numbers of optical ports. Effects of the number of candidate routes, add/drop ratio and the amount of historical data are also evaluated. 相似文献
9.
Although multi-domain survivability is a major concern for operators, few studies have considered the design of post-fault restoration schemes. This paper proposes two such strategies, based upon hierarchical routing and signaling crankback, to handle single and multi-link failure events in multi-domain IP/MPLS networks (also extendible to optical DWDM networks). Specifically, the hierarchical routing strategy relies upon abstracted domain information to compute inter-domain loose routes, whereas the crankback scheme applies signaling re-tries to restore paths in a domain-by-domain manner. The performance of these proposed solutions is then analyzed and compared via simulation. 相似文献
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12.
This paper argues for the need for convergence of protection and restoration schemes in today's telecommunication networks. Such networks are presented both in a layered context and from an end-to-end perspective. Such convergence is both necessary to ensure inter-working amongst a multitude of technologies deployed and desirable to ensure simplified operations. This paper further identifies the issues and inter-working items that need resolution in today's telecommunication and data networks in order to achieve inter working amongst various existing and emerging restoration and protection schemes in a layered and end-to-end context. End-to-end context covers the access, metro, and long haul dimensions of the network. It also encompasses both the services and the transport layers of the network in the context of multi-domain, multi service provider networks. Layering issues arise from the mix of technologies at several layers for example: optical transmission and CWDM/DWDM at physical layer, SONET/SDH framing and management at layer-1, ATM, MPLS, Ethernet, and resilient packet rings at layer-2, and finally IP and routing protocols at layer-3. Given that some degree of routing and signaling intelligence is migrating down to the optical layer equipment, this whole layering concept is currently in transition. This paper shows the need for convergence in the form of a two level protection and restoration scheme. A service independent layer and a mesh restoration capability at the routing layer. 相似文献
13.
A survey of inter-domain peering and provisioning solutions for the next generation optical networks
《Communications Surveys & Tutorials, IEEE》2009,11(1):33-51
The emergence of carrier grade transport technologies has led to a paradigm shift in inter-domain routing which became an important feature of the transport layer based on optical transmission and switching. While the new technologies have capabilities to provide end-to-end guaranteed quality of service (QoS), the lack of inter-operability between different technologies, administrative areas and control planes makes interdomain peering and provisioning below the conventional Internet Protocol (IP) layer a challenge. In this survey, we analyze various multi-domain routing models for emerging Layer 2 and WDM switched networks which have been proposed till date, and based on that survey, we highlight some open issues and future challenges pertaining to scalability, reliability, multi-domain QoS, control plane interworking and dynamic peering. 相似文献
14.
A next-generation optical regional access network 总被引:2,自引:0,他引:2
Kuznetsov M. Froberg N.M. Henion S.R. Rao H.G. Korn J. Rauschenbach K.A. Modiano E.H. Chan V.W.S. 《Communications Magazine, IEEE》2000,38(1):66-72
We describe an optical regional access network which combines electronic IP routing with intelligent networking functionality of the optical WDM layer. The optical WDM layer provides such networking functions as network logical topology reconfiguration, optical flow switching to offload traffic and bypass IP routers, wavelength routing of signals, protection switching and restoration in the optical domain, and flexible network service provisioning by reconfigurable wavelength connectivity. We discuss key enabling technologies for the WDM layer and describe their limitations. The symbiosis of electronic and optical WDM networking functions also allows support for heterogeneous format traffic and will enable efficient gigabit-per-second user access in next-generation Internet networks 相似文献
15.
《IEEE network》2001,15(4):28-35
An overview of current issues and challenges in lightpath routing for optical networks is given. An architecture is presented in which optical switches are deployed, usually in the core, to interconnect IP routers at the edges. Lightpath routing within this architecture follows the framework of generalized multiprotocol label switching. Our discussion pays particular attention to the aspects of optical routing that differ from routing in irrational IP networks. Such aspects include physical layer constraints, wavelength continuity, the decoupling of the control network topology from the data network topology, explicit routing with wavelength assignment, and diversity routing for fast protection. We also present an algorithmic framework for lightpath computation, highlighting the issue of wavelength continuity and the differences between lightpath computation and traditional IP route computation 相似文献
16.
Bart Puype Eva Marín-Tordera Didier Colle Sergio Sánchez-López Mario Pickavet Xavier Masip-Bruin Piet Demeester 《Photonic Network Communications》2012,23(2):172-182
Multilayer traffic engineering (MLTE) allows coping with ever-increasing and varying traffic demands in IP-over-Optical multilayer
networks. It utilizes cross-layer TE (Traffic Engineering) techniques to provision optical lightpath capacity to the IP/MPLS
(Internet Protocol/ Multi-Protocol Label Switching) logical topology on-demand. Such provisioning however causes optical connection
arrival rates that pose strong performance requirements to Routing and Wavelength Assignment (RWA) strategies. Collecting
up-to-date network information for the RWA with rapidly changing network states can be quite difficult. Exposing optical layer
state information to the IP layer in the overlay model, or transforming this optical layer information in a workable representation
in an integrated control plane is similarly problematic. Prediction-Based Routing (PBR) has been proposed as a RWA mechanism
for optical transport networks; it bases routing not on possibly inaccurate or outdated network state, but instead on previous
connections set-up. In this article, we propose to implement PBR as the RWA mechanism in the optical layer of a multilayer
network, and use the predictive capabilities of PBR to expose dynamic optical network information into the multilayer traffic
engineering algorithm with minimal control plane overhead. Some simulations show the benefits of using the PBR in the optical
layer for MLTE purposes. 相似文献
17.
Shanguo Huang Weihua Lian Xian Zhang Bingli Guo Pei Luo Jie Zhang Wanyi Gu 《Photonic Network Communications》2012,23(2):183-190
The routing issues in multi-layer and multi-domain optical networks have drawn much attention in current research. With the
introduction of the path computation element, routes can be calculated more efficiently in multi-domain optical networks.
However, the optimal degree of routing approach in multi-layer and multi-domain optical networks is also determined by the
clustering algorithms deployed for construction of hierarchical networks. Therefore, it is important to investigate the way
to evaluate the impact of the clustering algorithm on the routing approach (e.g., blocking probability) in optical networks
with dynamic traffic, which has not been studied sufficiently. In this paper, a novel method to describe and evaluate the
clustered structures generated by different clustering algorithms for hierarchical optical networks is proposed. This method
deploys a novel evaluation metric that represents blocking probability of clustered optical networks, so it can be used as
guidelines for designing clustered structures. Besides theoretical analysis, simulations are carried out on different network
topologies and clustered types to validate the effectiveness of the method presented. 相似文献
18.
Lei Guo Xingwei Wang Ying Li Chongshan Wang Hongming Li Hongpeng Wang Xin Liu 《Optical Fiber Technology》2009,15(2):192-196
In multi-domain wavelength-division-multiplexing (WDM) optical networks, the inter-domain routing is a challenge since each single-domain cannot view the full network topology. At the same time, survivability is also an important issue in optical networks since the failures of fiber links or network nodes may lead to a lot of traffic being blocked. In this paper, we study the survivability in multi-domain WDM optical networks, and propose a new survivable mechanism called load balanced domain-by-domain routing (LBDDR). In LBDDR, in order to obtain the efficient inter-domain survivable routes, we present the domain-by-domain routing (DDR) method which can find the intra-domain sub-working path and sub-backup path in each single-domain to form the inter-domain working path and backup path for each demand. In order to reduce the blocking probability, we present the load balanced routing method which can encourage the traffic to be uniformly distributed on the links with more free wavelengths. Simulation results show that, compared with conventional mechanism, LBDDR can obtain better performances. 相似文献
19.
探讨了IP over DWDM生存性的机制,研究了各个网络层的恢复特点以及不同层间相互作用对生存性的影响,明确了多层网络生存性的优点,从而得出光层能够提供最快的保护,较高的层能够提供智能恢复。最后提出了一种在光层的自动保护倒换的结构,这种保护能够优先考虑来自较高层的告警信息,使IP over DWDM网络做到智能化的快速恢复,为IP over DWDM网络的研究和建设提供了一定基础。 相似文献
20.
A differentiated optical services model for WDM networks 总被引:11,自引:0,他引:11
This article addresses the issues of scalable end-to-end QoS in metropolitan DWDM networks serving as transit networks for IP access networks. DWDM offering a few wavelengths has been deployed in the past in backbone networks to upgrade point-to-point transmission where sharing is based on coarse granularity. This type of DWDM backbone network, offering a few light-paths, provides no support for QoS services traversing the network. As DWDM networks with larger numbers of wavelengths penetrate the data-centric metro environment, specific IP service requirements such as priority restoration, scalability, dynamic provisioning of capacity and routes, and support for coarse-grain QoS capabilities will have to be addressed in the optical domain in order to achieve end-to-end QoS over a DWDM network. We propose a QoS service model in the optical domain called differentiated optical services (DoS) based on a set of optical parameters that captures the quality and reliability of the optical lightpath 相似文献